The development of tires which result in low fuel consumption has been prompted due to demands directed to energy saving.
To achieve these properties, attempts have been made to improve rebound resilience of a rubber compound of a tire.
U.S. Pat. No. 3,842,034 discloses that a rubber composition containing a nitrosoquinoline compound, such as 5-nitroso-8-hydroxyquinoline, improves the rebound resilience of the composition. The nitrosoquinoline compound has the general formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each a hydrogen atom, a hydroxyl group, an alkyl group, an aralkyl group, a cycloalkyl group or an aminoalkyl group.
When the nitrosoquinoline is added to a rubber composition for the tire tread, the rubber composition provides an excellent improvement in rebound resilience, but the wear resistance of the tire decreases.
After detailed investigations as to the effects of rebound resilience and wear resistance of many rubber compositions for tires, which contain many kinds of nitrosoquinoline compounds and the like, it has been found that the addition of compounds having a nitroso group results in a deterioration of the wear resistance of tire treads.